[Precaud]

I just completed these detailed mods for the SRD-7 adaptor:

Transforming the Stax SRD-7

Comments/questions welcome.

 

[Precaud]

Update: Recent communication with someone doing the mods to their SRD-7 made me take a closer look at the situation regarding the parallel LR circuit at the input. I had perhaps not made it clear enough that this input filter is ONLY needed with the SR-X headphones. This was based on using it in my systems, which do not have any tone controls.

Well, after using it with an integrated amp that has simple bass and treble shelving controls, I can now say that even those simple tone controls do a better job of correcting the SR-X tonal imbalance than the input LR filter does. So if your system has tone controls (analog or digital), you can skip the input LR filter.

This simplifies the mods even more, and removes the objections some might have to a) having an inductor in series with the amp output, and b) making mods to the adaptor that narrow its use to one model of headphone only.

The instructions have been updated to correct for this.

 

[Precaud]

Another update: A more accurate way to correct for the tonal imbalances of the SRD-7 / SR-X MkIII combo is with digital EQ, such as the excellent (and free) Equalizer APO (https://sourceforge.net/p/equalizerapo/wiki/Documentation/).

Configuration and filter files for the EQ have been added to the instructions. This sounds much better than using simple tone controls, by far...

 

[Precaud]

Yet another update: Mistakes happen. I recently discovered that I used the wrong calibration file for the network analzyer when making one of the measurements. I redid the measurement. Fortunately, the differences were minor and only two components in the optional passive filter circuit changed value. Everything has been updated.

I am susprised that noone has done these simple mods and reported on the results.